•Calculation of the amplitude

Calculation of the amplitude:

amplFC = CreateFCAmp[mesontreeinsert, AmplitudeLevel -> Classes, MomentumConservation -> True, EqualMasses -> False] ;

Specialization to the (7,3,3) isospin channel and isospin reduction:

amplFC2 = CheckF[(summ = SUNReduce[SUNReduce[#]] & /@ (Print["Expanding..."] ; tmp = Expand[#] ; Print["Reducing..."] ; tmp) ; suminds = (#[[1]]) & /@ Union[Cases[#, _SumOver, Infinity]] ; sums = If[suminds === {}, {I1, 1}, Sequence @@ ((({#, If[FreeQ[summ, #], 1, 8]} & /@ suminds)))] ; Print["Length of expression: ", Length[summ]] ; tmpii = 0 ; res = (If[IntegerQ[tmpii/100], Print[tmpii]] ; ++ tmpii ; SUNReduce[SUNReduce[Sum[WriteOutUMatrices[#], Evaluate[sums]], Explicit -> True, HoldSums -> False]]) & /@ summ) & /@ Take[amplFC /. {i1 -> 7, i3 -> 3, i4 -> 3}, {1, -1}], "KSPiPiCTolds.m"] ;

Further reduction and change to Mandelstam variables:

res1old = Simplify[((Simplify[(# /. D -> Sequence[] /. subpar /. udrules // MomentumExpand)] // MomentumCombine) /. {p2 + p3 + p4 -> -p1, -p2 - p3 - p4 -> p1} // ExpandScalarProduct // PropagatorDenominatorExplicit) /. MandelstamRules] & /@ amplFC2 ;

Converted by Mathematica  (July 10, 2003)